Basic GSM and Arduino Connection

basic_gsm.ino

#include <SoftwareSerial.h>
const byte rxPin = 2;
const byte txPin = 3;

SoftwareSerial SIM900(rxPin, txPin);
char msg;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  SIM900.begin(9600);
  Serial.println("Smoke Detector Console");
  SIM900.print("AT+CMGF=1\r");
  delay(100);
  SIM900.print("AT+CNMI=2,2,0,0,0\r");
  delay(100);
  SendMessage();
}

void loop() {
  // put your main code here, to run repeatedly:

}

void SendMessage()
{
  SIM900.println("AT+CMGF=1");    //Sets the GSM Module in Text Mode
  delay(1000);  // Delay of 1000 milli seconds or 1 second
  SIM900.println("AT+CMGS=\"+88**********\"\r"); // Replace x with mobile number
  delay(1000);
  SIM900.println("Home on Fire");// The SMS text you want to send
  delay(100);
  SIM900.println((char)26);// ASCII code of CTRL+Z
  delay(1000);
}